Appearance: Renji has long crimson hair, usually kept in a high ponytail, and his entire upper body is covered in tribal tattoo work.

Personality: Renji is about as eccentric as any other Soul Reaper. He varies from smug and cocky in his first appearances to downright angsty and depressed after his major defeats, but shows himself to be an incredibly serious and determined fighter when confronted with an actual challenge. Willing to fight, kill, and die for whatever he believes in, Renji is a dangerous man to those who stand in his way. He is similar to Ichigo Kurosaki in many aspects, and the two are mistaken for brothers in the anime's Bount arc. Ichigo claims they are cousins to keep things simple, allowing many hilarious situations to occur later, including comments over their unusually colored hair. A continuing gag in the series is Renji's nick name, red pineapple, referring to his crimson hair kept in a pineapple top-like ponytail. During a filler arc before the invasion of Las Noches, Renji wears a shirt with 'Red Pineapple' printed on the front, supposedly bought by Ichigo Kurosaki as a joke. He's even referred as "Aka Pine" during the Shinigami Cup segments.

Powers: Renji's zanpakutō is Zabimaru (蛇尾丸?, roughly "snake tail"). Zabimaru is a nue (a baboon with a snake tail), hence his name. Zabimaru's spirit is portrayed as battle-loving and proud, similar in personality to Renji. Both the snake and baboon are capable of speaking, though the baboon is usually the more dominant one.

Zabimaru's shikai command is "howl" (咆えろ, hoero?), although in the English adaptation of the anime the term used is "roar".[2] In such state, it transforms into a segmented blade with a pick-like protrusion on each segment. The segments are connected by a stretchable thread, making Zabimaru more useful as a whip than an actual sword. While Zabimaru can be stretched to incredible lengths in its whip form, Renji has a limit of three consecutive attacks before having to bring the segments of Zabimaru back together for recovery. Renji can also use his spiritual power to separate the segments and surround an opponent with them, allowing him to execute a one-shot omnidirectional attack called higa zekkō (狒牙絶咬?, "bite of a baboon's broken fang").

Hihiō Zabimaru.Zabimaru's bankai is Hihiō Zabimaru (狒狒王蛇尾丸?, "baboon king snake tail") and transforms Zabimaru into a massive version of its shikai form resembling a skeletal snake. Unlike its shikai, Zabimaru's segments are held together by Renji's spiritual power, allowing him to separate and reattach them at will. Even if a segment is damaged, Renji can simply detach it and reform Zabimaru. Zabimaru itself, in bankai form, does not literally "cut", Renji usually catches his opponent with the snake-head of his weapon and smashes his opponent into the ground with it. Zabimaru also gains a special technique known as hikōtsu taihō (狒骨大砲?, "baboon bone cannon") after Renji becomes more adept with using his bankai. The technique fires a dense blast of spiritual energy from Zabimaru's mouth. He can also use a much more powerful higa zekkō, where all the segments detach and sharpen using spiritual energy.

Bio:Renji Abarai came from the 78th district of Rukongai and grew up as an orphan with several other children, including Rukia Kuchiki. The company of children lived by hunting or stealing food and water. Though Renji and Rukia quickly discovered they had spiritual powers, they remained with their friends until they all died, which prompted them to become Soul Reapers for a better life. At the Soul Reaper academy, Renji was admitted into the top class, being very adept at swordsmanship, although quite inept at kidō. At the academy, Renji befriended Izuru Kira and Momo Hinamori. His relationship with Rukia became distant after her adoption by the Kuchiki family since he felt he had no place interfering with her life now that she was a noble, despite the fact they both seemed to regret losing the company and confidence of the other.

Renji, Kira and Hinamori served under Sōsuke Aizen and Gin Ichimaru in the 5th division, after which Kira and Hinamori were put under Ichimaru and Aizen in the 3rd and 5th divisions respectively. The rebellious Renji was moved to the 11th Division and eventually rose to the 6th seat. During his time in the 11th Division, he befriended Ikkaku Madarame, who taught Renji how to fight. On the same day Rukia headed for the human world, Renji was promoted to lieutenant of the 6th Division.[3] After meeting Byakuya Kuchiki when Byakuya adopted Rukia into the Kuchiki family at the academy, the 6th Division's captain, Renji's greatest dream has been to surpass him in strength.